1. Field
The embodiments discussed herein relate to a semiconductor device and a method for manufacturing the semiconductor device.
2. Description of Related Art
Materials including GaN, AlN, InN, and a mixed crystal of these materials, which are included in nitride semiconductors, have a wide band-gap and are used in high-output electronic devices, short-wavelength light-emitting devices, and the like. Field-effect transistors (FETs), for example, high electron mobility transistors (HEMTs) are used in high-output-high-efficiency-amplifiers or high-power switching devices, and the like. In an HEMT including an electron supply layer having AlGaN and an electron transit layer having GaN, strain due to a difference in a lattice constant between AlGaN and GaN may occur in AlGaN and piezoelectric polarization may occur. Since a high-concentration two-dimensional electron gas is generated by the piezoelectric polarization, a high-output device may be provided.
For example, related are is disclosed in Japanese Laid-open Patent Publication Nos. 2002-359256, 2007-19309, and 2009-76845.